马铃薯块茎生长过程中内源赤霉素和脱落酸含量的变化

以紫花白和晋薯２号两个品种为材料，研究了马铃薯同一个体植株中，处于不同生长阶段上的块茎，其内源ＧＡ３和ＡＢＡ含量的变化规律．结果表明：开始形成的块茎（块茎直径１ｃｍ左右）中ＡＢＡ和ＧＡ３含量最高，但ＧＡ３／ＡＢＡ的比值则较低；之后随着块茎的膨大，ＡＢＡ和ＧＡ３的含量均逐渐降低，但ＡＢＡ的降低速度大于ＧＡ３，从而使ＧＡ３／ＡＢＡ的比值逐渐增高，到块茎成熟时，ＡＢＡ和ＧＡ３都有所增加。而由块茎迅速膨大到成熟的过程中，ＧＡ３／ＡＢＡ的比值则又逐渐降低。两个品种在块茎生长过程中，内源ＧＡ３和ＡＢＡ的含量具有相似的变化规律．成熟期块茎平均直径较大的紫花白，当块茎直径小于５ｃｍ左右时，其中ＧＡ３的含量大于相应大小的晋薯２号，后期两个品种之间则基本无差异；而ＡＢＡ的含量在两个品种之间则始终无多大差异；因此使ＧＡ３／ＡＢＡ的比值在块茎直径小于５ｃｍ以前紫花白大于晋薯２号。因此我们认为ＧＡ３和ＡＢＡ在块茎开始形成与膨大及成熟的整个生长过程中，对块茎的形成和生长发育具有负反馈调节与协同作用．

STUDY ON THE CONTENT OF INTERNAL GA_3 AND ABA IN GROWING POTATO TUBER

The contents or ABA and GA3wcrc dctcrmincd in different size tubers of Zihuabai andJinshu 2. The tubers arc in different expanding stage and from the same potato plant. Thecontent of ABA and GA3in per-gram fresh initiation tuber (the diameter is about 1 cm) ishigher than the later stage tuber, but the ratio of GA3/ABA is lower at the same time. With the tuber expansion the contents of the two hormones decrease to a lowest point and the ratio increases gruadully to a highest point at the later expanding stage, then the contents of hormones increase a little and the ratio dccrcasc a little. The content change rule or the two cultivars is very similar. But the content or GA3in Zhuabai, the average size of its mature tuber being bigger than that of Jinshu 2, is always higher than that in Jinshu 2 of the same size before the diameter reaches 5cm, but no remarkable diffcrcncc is found bctwccn the GA3contcnt of the two cultivars in the later stage and between the ABA content of the two cultivars for all growth stage, so the GA3/ABA ratio or Zihuabai is higher than that of the Jinshu 2 before the diameter reaches scm. All of these suggest that GA,and ABA have a negative feedback and coordination effect on tuber initiation, cxpandion and dormancy.